Mechanical digital watch

ABSTRACT

A mechanical digital watch comprises a continuously rotating minute disc having the numerals 0 through 59 positioned consecutively about the periphery thereof and an hour disc having the hour numerals thereon which is driven by a cannon pinion through a Geneva drive pinion arrangement. The hour disc is stationary during approximately 54 minutes of each hour and rapidly shifts to the next digit between 3 minutes before each hour to 3 minutes past each hour. The time indicating discs are in gear engagement with each other which prevents them from falling out of synchronism with each other under shock.

[ Dec. 17, 1974 1 MECHANICAL DIGITAL WATCH [75] Inventor: Paul Wuthrich, Watertown, Conn.

[73] Assignee: Timex Corporation, Watertown,

Conn.

' [22] Filed: June 10, 1974 [21] Appl. No.: 477,731

[56] References Cited UNITED STATES PATENTS Youhouse 58/125 B Heuer 58/125 B 3,685,283 8/1972 Bamat 58/126 A Primary Examiner-George H. Miller, Jr.

[57] ABSTRACT A mechanical digital watch comprises a continuously rotating minute disc having the numerals 0 through 59 positioned consecutively about the periphery thereof and an hour disc having the hour numerals thereon which is driven by a cannon pinion through a Geneva drive pinion arrangement. The hour disc is stationary during approximately 54 minutes of each hour and rapidly shifts to the next digit between 3 minutes before each hour to 3 minutes past each hour. The time indicating discs are in gear engagement with each other which prevents them from falling out of synchronism with each other under shock.

10 Claims, 6 Drawing Figures PATENTEL DEC] 71974 sum 10F NQE M 7 3.854.280 swan 20F PATENTEL Chill 71974 BACKGROUND OF THE INVENTION The present invention relates to watches and particularly to a mechanical digital watch having a unique drive arrangement for the time indicating means.

The prior art includes US. Pat. No.' 3,685,283 to Bamat which issued Aug. 22, 1972 and discloses a digital watch including a pair of adjacent rotatable indicating discs. The indicia on the discs pass adjacent the geometric central axis of the case wherein they are viewed through respective window means.

US. Pat. No. 418,334 to Jaccard which issued Dec. 31, 1889 discloses a mechanical digital system wherein a continuously rotating minute hand periodically advances an hour dial by suitable gearing means.

Almquist US. Pat. No. 2,040,421 which issued May 12, 1936 discloses a numerical clock wherein a synchronous motor drives a minute dial and a Geneva gear system is used to drive a tens minute dial and an hour hand.

Also of interest in this general area are US. Pat. No. 2,645,896 which. issued July 21, 1953 and US. Pat. No. 1,997,570 which issued Apr. 16, 1935. These patents mentioned above are merely intended to be representative of the prior art and are not intended tobe an allinelusive listing of such patents. 1

One of the main problems faced by the prior art patents mentioned above is the rapid switching of the hour dial so that the complete number is viewed through the window means for as long a period as possible and the change to a succeeding hour is condensed into a relatively short period. Another disadvantage of the prior art occurs due to the use of complicated indexingarrangements which fall out of synchronism if subjected to rough wear or sudden shocks. The present invention is designed to overcome these problems.

SUMMARY OF THE INVENTION The present invention relates to a mechanical digital watch which includes a conventional second hand and a continuously rotating minute disc with suitable indicia located thereon and a concentrically mounted hour disc of larger diameter than the minute disc with indicia arranged about the periphery thereof; The hour disc is maintained in a stationary position with one hour numeral showing in the center of a dial window du'ring approximately 54 minutes of each hour; A cannon pinion coupled to the watch drive means actuates a Geneva gear portion of an hour drive pinion once each hour, driving the pinion by one-fifth revolution when a protruding nose on the cannon pinion engages the Geneva pinion. An upper gear portion of the Geneva drive portion (the hour drive pinion), engages teeth on the hour disc thereby advancing the hour disc during a short interval at the turn of each hour. As a feature of the present invention, the hour disc advances during an interval of approximately 6 minutes at the turn of each hour without the use of detenting springs. Furthermore, since the time indicating discs are in gear engagement with each other, they are prevented from falling out of synchronism with each other if a sudden shock is received.

Accordingly, an object of this invention is to provide a new and improved mechanical digital watch.

Another object of this invention is to providev a new and improved mechanical digital watch wherein the hour change is effected in a rapid manner at the turn of each hour.

A further object of this invention is to provide a new and improved digital watch wherein the hours and minutes are indicated on respective discs which are in gear engagement with each other to eliminate problems resulting from sudden shocks or rough use.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of this invention may be seen from thefollowing description whcn viewed in conjunction with the accompanying drawings wherein:

FIG. 1 is a plan view of the mechanical digital watch with portions shown in phantom;

FIG. 2 is a cross-sectional view of the watch of FIG. 1 taken along the line 2-2 of FIG. 1;

FIG. 3 is a partial cross-sectional view taken along the line 3-3 of FIG. 1 showing the relationship of the minute and hour indicia;

FIG. 4 is a partial plan view taken along the line 4-4 of FIG. 2 showing the interaction of the Geneva drive pinion with the hour disc gear;

FIG. 5 is a partial plan view taken along the line 55 of FIG. 2 showing the cannon pinion in engagement with the Geneva drive pinion; and,

FIG. 6 is a partial plan view with portions cut away to show the cannon pinion and the minute and hour discs.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, the invention comprises a mechanical digital watch 10 having a case 11 with a conventional stem 12 protruding outwardly therefrom. The mechanical digital watch 10 of FIG. 1 includes a dial 13 having window means 14 and 16 through which the hour indicia l7 and minute indicia 18, respectively, may be viewed. The hour indicia l7 arelocated on an hour disc 19 which rotates about the watch drive shaft 21 while the minute indicia 18 are positioned about a minute disc 20 of lesser diameter which continuously rotates about the drive shaft 21. The window means 14 and 16 are located in the middle of the watch 10 and on opposite sides of the drive shaft, with the window 14 being located to the viewers left and the window 16 to the viewers right. It is, of course, possible to envision an alternative arrangement with the hours and minutes being viewed through a single window (not shown) either to the left or right of the drive shaft.

FIG. 2 shows a drive coupling assembly 22 which includes shaft 21 on the upper portion thereof. The coupling assembly 22 is connected to a conventional drive arrangement (not shown) and is pivotally mounted in members 23 and 29. A seconds hand 24 is mounted to the shaft 21 for rotation above the dial 26. The drive arrangement also includes a minute pipe or sleeve 27. The entire drive assembly is mounted between frame member 29 and the dial 26 which are mounted together at the periphery of the watch 10. The minute disc 20 is press fit on sleeve 27 and to the shoulder 25 of member 28 for continuous rotation thereabout and is held in place by a spring member 31.

The concentrically arranged free running hour disc 19 is generally located beneath the minute disc 20 and extendsoutwardly from sleeve 28 which in turn is supported on shoulder 35. The end portion 32 of the disc 19 is located above the main body portion 33 and at a slight downward slope. The hour indicia 17 are located on the outer portion of the hour disc. A cannon pinion 34, see FIG. 6, is mounted to sleeve member 28 and includes protruding nose portion 37 which engages Geneva drive pinion 38 once during each hour to rotate the pinion 38 by one-fifth revolution. The Geneva drive pinion 38 is part of a pinion hour drive member 39 which is mounted for rotation about shaft 41. The Ge- 1 neva drive pinion 38, see FIG. 5, comprises five teeth shaped in a predetermined Geneva configuration which comprise the lower portion of member 39. The upper portion of member 39 comprises a drive pinion 42 having five teeth 43 which consecutively engage the twelve teeth 45 of the hour disc gear 44 which projects downwardly from the hour disc 19.

In operation, the seconds are indicated by the conventional seconds hand 24 while the minute indication is viewed through the window 16 on a continuously rotating minute disc 20. The hour disc 19 remains stationary with one hour numeral 17 showing in the center of window 14 during approximately 54 minutes of every hour. At approximately 3 minutes to each hour, the Geneva hour drive pinion 38 is engaged by protruding nose 37 on the cannon pinion 34 and is rotated by about one-fifth revolution. The upper gear portion 44 of the hour drive pinion arrangement 39 engages the hour disc teeth 45 on gear 44 to advance the hour disc at the turn of the hour in a rapid manner terminating at approximately 3 minutes after the hour.

With the present invention, it is thereby possible to achieve an extremely rapid change in the hour indication in a mechanical digital watch without the use of conventional detenting springs and the disadvantages associated therewith. Furthermore, since the hour disc 19 and the minute disc 20 are in' gear engagement with each other, they remain in synchronism even under severe conditions of use.

While the'invention has been explained by a detailed description of certain embodiments, it is understood that various modifications and substitutions can be made in any of them within the scope of the appended claims which are intended also to include equivalents of such embodiments.

What is claimed is:

I. A digital watch having an outer case and watch drive means located therein comprising:

a dial mounted to said case and having at least one window therein,

a drive shaft coupled to the watch drive means and having a seconds hand mounted thereon,

a minute disc coupled to said shaft and having indicia located on the periphery thereof for indicating minutes, said indicia being viewable through said window in the dial,

an hour disc concentrically coupled to said drive shaft and having hour indicia located about the periphery thereof, said indicia being viewable through said window in the dial, said hour disc having a disc gear portion extending therefrom,

a cannon pinion coupled to said drive shaft and having a protruding nose portion on the periphery thereof, and,

a pinion hour drive assembly comprising 21 Geneva drive pinion actuated each hour by said cannon pinion and a pinion gear portion which engages the hour disc gear to drive said gear during a relatively short interval at the turn of each hour thereby rapidly changing the hour indicia in said window.

2. A digital watch in accordance with claim 1 wherein:

the minute disc is coupled to the drive shaft for continuous rotation,

the cannon pinion is coupled to the drive shaft to complete one rotation each hour, and,

the hour disc is coupled about said drive shaft and held fixedly in position by the pinion hour drive assembly except for a short interval at the turn of each hour when said assembly is engaged by the cannon pinion.

3. A digital watch in accordance with claim 2 wherein:

the hour disc gear has twelve protruding teeth thereon and the pinion drive portion of the pinion hour drive assembly has a plurality of protruding teeth which engage said hour disc gear teeth to drive said gear during a short interval at the turn of each hour.

4. A digital watch in accordance with claim 2 wherein:

the Geneva drive pinion portion of the pinion hour drive assembly comprises a Geneva gear configuration having a plurality of teeth, equal in number to the teeth on the pinion drive portion, which are engaged by the nose portion of the cannon pinion once each hour during the turn of said hour to rapidly rotate said hour disc.

5. A digital watch in accordance with claim 2 wherein:

the window opening in the dial comprises a first hour window and a second minute window located on opposite sides of the drive shaft with the hour window being located to viewers left and the minute window being located to viewers right.

6. A digital watch in accordance with claim 2 further including:

a shaft mounted within said case in a parallel relationship with the drive shaft wherein said pinion hour drive assembly is mounted for rotation thereon.

7. A digital watch in accordance with claim 2 wherein:

the minute disc is mounted to said drive shaft for continuous rotation and wherein the hour disc is coupled to said drive shaft for rotation during a period of approximately 6 minutes at the turn of each hour to effect rapid rotation of said hour disc.

8. A digital watch in accordance with claim 2 wherein:

the hour disc comprises a main body portion substantially perpendicular to the drive shaft and outer sloping portion having the indicia located on the upper surface thereof.

9. A digital watch in accordance with claim 2 wherein:

the pinion hour drive assembly comprises an upper pinion gear portion and a lower Geneva drive pinion portion, and,

the hour disc includes a downwardly extending hour disc gear into which engages the pinion gear portion of said assembly to hold said hour disc in place under shock.

10. A digital watch in accordance with claim 2 wherein:

the window opening comprises a single window through which the hour indicia and minute indicia may be viewed. 

1. A digital watch having an outer case and watch drive means located therein comprising: a dial mounted to said case and having at least one window therein, a drive shaft coupled to the watch drive means and having a seconds hand mounted thereon, a minute disc coupled to said shaft and having indicia located on the periphery thereof for indicating minutes, said indicia being viewable through said window in the dial, an hour disc concentrically coupled to said drive shaft and having hour indicia located about the periphery thereof, said indicia being viewable through said window in the dial, said hour disc having a disc gear portion extending therefrom, a cannon pinion coupled to said drive shaft and having a protruding nose portion on the periphery thereof, and, a pinion hour drive assembly comprising a Geneva drive pinion actuated each hour by said cannon pinion and a pinion gear portion which engages the hour disc gear to drive said gear during a relatively short interval at the turn of each hour thereby rapidly changing the hour indicia in said window.
 2. A digital watch in accordance with claim 1 wherein: the minute disc is coupled to the drive shaft for continuous rotation, the cannon pinion is coupled to the drive shaft to complete one rotation each hour, and, the hour disc is coupled about said drive shaft and held fixedly in position by the pinion hour drive assembly except for a short interval at the turn of each hour when said assembly is engaged by the cannon pinion.
 3. A digital watch in accordance with claim 2 wherein: the hour disc gear has twelve protruding teeth thereon and the pinion drive portion of the pinion hour drive assembly has a plurality of protruding teeth which engage said hour disc gear teeth to drive said gear during a short interval at the turn of each hour.
 4. A digital watch in accordance with claim 2 wherein: the Geneva drive pinion portion of the pinion hour drive assembly comprises a Geneva gear configuration having a plurality of teeth, equal in number to the teeth on the piNion drive portion, which are engaged by the nose portion of the cannon pinion once each hour during the turn of said hour to rapidly rotate said hour disc.
 5. A digital watch in accordance with claim 2 wherein: the window opening in the dial comprises a first hour window and a second minute window located on opposite sides of the drive shaft with the hour window being located to viewer''s left and the minute window being located to viewer''s right.
 6. A digital watch in accordance with claim 2 further including: a shaft mounted within said case in a parallel relationship with the drive shaft wherein said pinion hour drive assembly is mounted for rotation thereon.
 7. A digital watch in accordance with claim 2 wherein: the minute disc is mounted to said drive shaft for continuous rotation and wherein the hour disc is coupled to said drive shaft for rotation during a period of approximately 6 minutes at the turn of each hour to effect rapid rotation of said hour disc.
 8. A digital watch in accordance with claim 2 wherein: the hour disc comprises a main body portion substantially perpendicular to the drive shaft and outer sloping portion having the indicia located on the upper surface thereof.
 9. A digital watch in accordance with claim 2 wherein: the pinion hour drive assembly comprises an upper pinion gear portion and a lower Geneva drive pinion portion, and, the hour disc includes a downwardly extending hour disc gear into which engages the pinion gear portion of said assembly to hold said hour disc in place under shock.
 10. A digital watch in accordance with claim 2 wherein: the window opening comprises a single window through which the hour indicia and minute indicia may be viewed. 